Insufficient data. However, given the larger percentage of the population that has elected to reject vaccination and will be a favorable medium for epidemic spread, I’m sure we’ll find out.
For what it is worth, while efficacy of the current vaccines against symptomatic infection is measurably reduced vice the B1.167.2 (‘Delta’) variant, it does still seem to be quite effective against severe morbidity requiring hospitalization and very good against mortality, as well as (anecdotally, at least) reducing ‘long-haul’ symptoms. There is already talk of booster shoots using a modified vaccine, which would also help people who are immunocompromised or have not maintained a robust immune response.
The real danger is not the ‘Delta’ variant, which is more infectious but does not (as far as currently data shows) cause significantly more serious disease, but a mutation to that variant that is more virulent. There is, in fact, a ‘Delta Plus’ variant with a mutation in the K417 amino acid that does appear to be more capable of evading antibodies although whether it causes more hospitalizations than other variants is unclear. However, given the poorly understood viral pathogenesis it seems quite likely that there are potential mutations, particularly in the envelope (E) protein, that could significantly increase virulence.